Plot horizontal dendrogram with hanging leaves? (R)

Question

I would like to create a dendrogram plot with horizontal labels, but having the leaves hang according to their height, instead of just drop to the edge of the plot.

Example:

par(mfrow = c(1,2))
hc <- hclust(dist(USArrests), "ave")
plot(hc) # a plot with hanging branches
plot(as.dendrogram(hc), horiz = TRUE) # a horizontal plot, but the branches are not hanging

Any suggestion on how this can be programmed?

Thanks.

Answer 1

You can change the value of hang in the as.dendrogram function.

par(mfrow = c(1,2))
hc <- hclust(dist(USArrests), "ave")
plot(hc)
plot(as.dendrogram(hc, hang=0.02), horiz = TRUE)

Answer 2

For the record, I've implemented a hang.dendrogram function (in the dendextend package), to allow hanging a dendrogram also after is was created (and not only during the changing from hclust to a dendrogram). Here is how to use it:

install.packages("dendextend")
library(dendextend)

dend <- as.dendrogram(hclust(dist(USArrests), "ave"))
par(mar = c(5,5,5,5))
plot(hang.dendrogram(dend), horiz = TRUE)